1. Field of the Invention
The present invention relates to an electronic component mounting apparatus and an electronic component mounting method that mount electronic components onto a circuit board or the like.
2. Related Art of the Invention
Various bonding methods for bonding a bump electrode of an electronic component to an electrode on a printed circuit board are known. For example, ultrasonic bonding is one bonding method capable of bonding an electronic component to a circuit board in a short time.
The ultrasonic bonding is a method which vibrates an electronic component by ultrasonic vibration while pressing the electronic component against a circuit board to cause local slippage at the bonding interface between the circuit board and the electronic component to break up and blow away a coating, thereby electrically bonding an electrode of the electronic component to an electrode on the circuit board at the atomic level.
Primarily referencing FIG. 14, a configuration and operation of a conventional electronic component mounting apparatus that uses ultrasonic bonding mentioned above will be described.
FIG. 14 is a schematic side view of a conventional electronic component mounting apparatus.
The conventional electronic component mounting apparatus performs bump bonding of an electronic component 8 to a circuit board 9 (see Japanese Patent Laid-Open No. 2004-134563, for example).
The entire disclosure of Japanese Patent Laid-Open No. 2004-134563 is incorporated herein by reference in its entirety.
The conventional electronic component mounting apparatus includes a mounting head 100 having a horn 91 having an ultrasonic transducer 92 fixed at one end and clamping a sticklike holding tool 93 at the other end. The horn 91 extends in a horn axis line I.
Ultrasonic vibration applied by the ultrasonic transducer 92 travels in the traveling direction along the horn axis line I to the holding tool 93 as a longitudinal wave whose vibration in the medium is parallel to the traveling direction.
The electronic component mounting apparatus vibrates the electronic component 8 through the holding tool 93 by the ultrasonic transducer 92 while pressing the electronic component 8 against the circuit board 9 through the holding tool 93 by a pressing unit (not shown), thereby electrically bonding an electrode of the electronic component 8 to an electrode on the circuit board 9.
Referring to FIG. 15, the mounting head 100 of the conventional electronic component mounting apparatus will be described in further detail.
FIG. 15 is a schematic perspective view of the mounting head 100 of the conventional electronic component mounting apparatus.
At the tip of the horn 91, the holding tool 93 is clamped by two split portions 911 and 912 in the direction perpendicular to the direction of ultrasonic vibration applied by the ultrasonic transducer 92.
More specifically, a so-called split clamp structure is provided at the tip of the horn 91. The horn 91 uses a fixation screw 94 that fastens the two split portions 911 and 912 formed by the split with equal torque to clamp the holding tool 93 inserted in a through-hole 913.
The two split portions 911 and 912 are disposed symmetrically with respect to the horn axis line I of the horn 91 in order to evenly transmit ultrasonic vibration applied by the ultrasonic transducer 92 to the holding tool 93.